The subject matter disclosed herein relates to a door interface for a circuit breaker drawout mechanism. In particular, the subject matter disclosed herein relates to an interface that provides ingress protection while the circuit breaker is located in different positions within the draw out mechanism.
Drawout circuit breakers often include a mechanism for moving the breaker in and connecting the breaker to corresponding electrical contacts, a location known as the “racked-in” position. When in the racked-in position, the circuit breaker is coupled to the main electrical circuit and provides the interruption functionality for which it is intended. If the drawout mechanism is reversed to the “racked-out” position, the circuit breaker is disconnected from the electrical contacts and the main electrical circuit. The circuit breaker may be moved to the racked-out position, for example, when maintenance is performed on the main electrical circuit. Typical racking mechanisms often include a third or test position. In the test position the circuit breaker can be closed, opened or tripped in order to check internal and external accessories such as auxiliary switches, shunt trip and under voltage and secondary circuits.
During each of the positions, it is desirable for the drawout mechanism to provide ingress protection (IP) such as IP4X defined by international standard IEC 60529. IP sets limits on openings in the equipment that would allow the insertion objects, such as a finger or wires for example, that could contact electrically live components. In the case of IP4X, openings cannot allow an object larger than 1 mm.
While existing circuit breaker drawout mechanisms are suitable for their intended purposes, there still remains a need for improvements particularly regarding the interface between the circuit breaker and the drawout mechanism that provides for ingress protection and allows the drawout housing door to be opened when the circuit breaker is in the racked-in, racked-out and the test positions.